Automatic telephone system



Nov. 1l, 193i?. M. TcHoUBRlTCH 1,781,609

AUTOMATIC TELEPHONE SYSTEM Filed April 4, 1928 2 Sheets-Sheet 1 @gil ouTqo/NG LINK Z0 LEADS 7'0 MEANS FOR START/Aff (ALAI/YQ' Ndf'll/NE Nov. 11, 1930. M, T CHOUBRWCH 1,781,609

AUTOMATIC TELEPHONE SYSTEM Filed April 4, 1928 2 sheets-sheet y 2 i5 the two subscribers.

Patented Nov. 11, 1930 vUNi'rin .,s'rATss Frisur OFFICE MICHEL TCHOUBRITGH, or sUcY-ENLBRIE, FRANCEy AUTOMATIC TELEPHONE SYSTEM applicati@ inea Aprile, 1928, seriai No. 267,396, and in Franiiprn 11, 1927.

The presentinvention relates to anV automatic-selector relayapparatus intended for telephony. The essential features of the new apparatus will appear froin'the following description:

It is known that atelephone line, to give good results,'shoiild be balancedV in order better to avoid disturbances and losses due to an unbalanced state of the lines.

fHence, the adoption of a solutionl which consists in making .independent the feed of each vof the two subscribers (calling and Vcalled parties), while providing afr'eepath for the modulatedjtalking current between This implies the use of an incoming trunk andan outgoing trunk,

connected together by `means of suitable ilters traversed by the'modulated talking cur* rent, but opposing the passage of the feed y current proper. i

In conformity with this principle there have been constructed a number of automatic relay telephone systems in which use is made of trunk lines, oiiefthe incoming, and the y*other the outgoing trunk.

Each subscribersline is crossed lby 'two' lines (incoming and outgoing) ofeach auxiliary line, and-each point of intersection comprises two selector relays, `the functions s of which arep'first, to connect the'subscrih ers `line with the outgoing trunk, and second,

to connect the saine subscribers line 4with the s n p saine selector relay is capablel of connecting incoming trunk of thesame auxiliary line Y' (accordingly as thesubscriber is the calling or thecalled party) n.' rlhe number of selector relays is then double the product of thefnumber of subscribers the number of auxiliary lines, which renders automatic relay telephony practically impossible' i biiiations consistingyin considerably augmenting the number of contacts or certain 'relays, several subscribers .being grouped lon serious rdiilicultiesv in Vthe upkeep of relays K too greatly encumbered with contacts andV disf turbaiice of trafic, the number of simultane- Certain combinationsV ofgrouping the subf scribers lines have also been tried, these coni-r ousconversations in a predetermined group not being capable of exceeding a fraction of the number of auxiliary lines belonging to this group. v

The automatic l.relay selector apparatus forming the subject of the present invention, andv which'tinay be applied to all distribution networks, whatever their importance, differentiates in this regard from all automatic `relay selector apparatus known at the `pres- Vthe incoming linkwith .the incomingl trunk and, on theother hand, connection of the outgoing linkwith the outgoing trunk, one of the two links vbeing automatically insulated from the corresponding subscribers linebyvthe reversing relay of said subscribers line, accordingly asthe latter is the calling or the called party.

By means of this combinatioinone and the any subscribers line with vthe outgoing trunk, i

ber of's'ubsc-ribersiby thenumber of auXil` iary'lines, that isto'say, thatin the new system, the number of selector relays is only half thernumber of the same relays required by known systems to attain the same result.

in A iiotlier-V 'characteristic of theV invention consists in the formation ofthe dial group,

which comprises as many counting chains as there are digits to vfrom a subscribers numbei,y each of. said cha-insbeingactuated according tothe counting of the unit-s, the tens, the hundreds, and `so 0in s g l lis excited by means of two distinct circuits traversed respectively by uneven (odd) current impulses flowing through the rest con tact of each of the even relays, and byeven current impulses shunted` on each of the odd relays, the division of the impulsesV (pro-` duced by the counting dial of the calling party) into even and odd impulses being effected by means of C1-regulator called an impulse distributor preceding each count- ,ing group, said impulse distributor being Connected with relays to automatically direct the seriesv of 'impulses from one counting chain into the following counting chain, in proportion as the impulses of the same series are terminated.

l Through the resolution of the impulses of the counting dial into odd and even impulses,a slight retardation in the operation freely and independently, which eliminates Y adjustment of the relays, the sensitiveness of which plays only a. secondary part; this is an appreciable advantagev as compared with what takes place in known systems where the impulsesV succeed each other bymeans of a single circuit (cascade mounting) Allthecounting groups ofthe new automatic relay selector circuit (groups which V` are, for example, two for each hundred subscribers) are connected to a single connecting group-or connecting chain, formed by ten decimal relays controlled individually by a work contact of each relay of the-hundreds counting chain, each connecting relay in turn controlling ten contacts, each fixed part of which terminates at the control circuit of a called subscribers line, the movable part of each of said contacts terminating in a work Contact of each relay of the units counting chain.

The complete system is represented in two views in which Figure f1 represents a numf ber of individual equipments or subscribers lines which cross a network of auxiliary lines i of which onel'has been represented with itsv conversation cord. r i

Figure 2 represents a numbering group Aproce-eding from the impulse distributor, and

the 'connector common to the numbering` groups. Y

` The accompanying drawing shows by way of example an automatic relay selector circuitV ofthe' two digit type adapted to serve 100 lines numbered from 01 to'OO'but on which,

avancee for greater simplicity, only live subscribers lines are shown. For greater clearness this drawing shows only three trunk lines on the ten, a single conversation line (terminating each auxiliary line), a single marker group instead of two, and finally a single connecting chain. Y

In this example we have designatedby I. Each subscribers line,

IT. The trunk lines,

III. A conversation circuit or line (that of auxiliary line H2) comprising among others a feed group,

TV. A marker group formed by two counting chains and preceded by the regulator or impulse distributor,

V. The connecting circuit or connecting group or connecting' chain common to the counting groups.

On the diagram shown on the drawing, vthe calling lines are represented in heavy lines, the called lines are indicated by ydotted lines and the lines of the local circuits are indicated by thinlines.

For the purpose of simplifying the description which follows, the .device forming the jsubj ect of the present invention is described by the elements of which it is constituted and at the same time this operation will also be described.

)Vlien the telephonie combination (not illust-rated in drawing) is unhooked the wires 1 and 2 are connected across the said combination. The relay A (relay of the calling line) which,.for this reason, is connected to the *pole of the central battery by means of the wires 1, 2 and 3, comes into action and connects the wires 1 and 2 respectively, to the wires i and 5 and connects the Mpole to the wires 6 and 115, that is to say to the wind-V ing of the relay D (damping relay on the calling side). This comes into action and connects the wire 8 of each relay C1 C2 C3 etc. (selecting relays of the auxiliary lines) respectively tothe wire 9 of the speaking line corresponding with each of the relays under consideration. f

At this moment two conditions arise:

All the auxiliary lines II may be unoccupied or some of these lines may be occupied.

Hereinafter it is assumed that the auxiliary lines Ill and H3V are occupied and that the auxiliary line IP is free. Y

One end of the windings ofi all the relays C are branched by means of the wire 13 and the relays L (releasing relays) and K (guard ing relays) of the corresponding speaking line, from the ,pole of the central battery. In order that one of the 'relays C can come into action it is necessary, when unhooking battery to the other end of the winding of the relay in question. This connection is effected by the speaking line of the auxiliary line f H2, that is to say by the following circuit:

vthe combination, to connect the -l-pole of theV -pole of the battery', contact of therest re-l lay L, Wire.13,.Winding of relay C2 of the subscribers line No. 17 (Which is assumed to be that of the calling subscriber), rest contact of lthe relay, Wire 8, Working contact of relay D1, Wire 9, rest contact of the relay K, Wire 100 and -tpoleoic the central battery (by meansfof the Working contact lol the relay K of the preceding speaking line Which it has been assumed is engaged). The connection Withthe -l-pole of the battery, Which connection determines the bringing into action of the relay C cannot be effected eXceptby means of one line at the time, Whether the lines are free or engaged.

The relay D1,.When coming yinto action, closes all the circuits passing through' its Working contacts, a single one of the relays C is placed under tension, all the others being on a non-supplied circuit.

The relay Cgcomes into action, thus determining ay series of operations Which take place almost simultaneously andrwhich are described separately hereinafter. i

When the relay C2 comes into action, the contact of its YWinding leaves the Wire 8 so as to be `connected to the Wire 14 Which' causes the Winding ofthe relay C2 in question to be connected in series With one. end of the Winding of the relay B, (relay for cutting oil the supply) the other end of the Winding of relayv B being permanently connected to the -lpole of the battery. A

The relay B When it comes into action, cuts oli' they supplyof the subscribers line, establishesthe Working circuit of the relay by the connection of the Wires 3. and 6, sepas rating the pole of the battery from the Wire 88, causingthe relay Dto return to rest and separating the Wires 78 and 79 Which serve 'to' prepare Ythecalled side. f

' y Vf hen the relay C2r comes into action it con nects the Wires 4. and 5 respectively to the vWires 11 and 12 Which lead to the tWo poles of the Acentral battery by means of the Wind- Caned Side) y This latter relay in turn comes into action ings o-fthe relay (speaking relay on the andk connects the -l-pole of the battery to the Y Wires`15 and 16. As the Wire 15 is connected' to the Winding of the relay K, this comes into action, cuts the circuit 9-100 and establishes thefcircuit 100--101 (which results inl the occupation of the line of the auxiliary .line H2) the relay K connects, onthe other hand,

rthe ,-l-polefof the central battery to thefiolloWingline by means of they Wire 100` passing from the preceding line and by means olf the the lines ata time.

The relay K also connects the -l-p'oleof the battery to the Wire 17 Whichen'sures general guarding during` the Whole duration of the conversation.` The relay VK alsoyconnects the the followingv circuit Y:V

-pole of the battery to the Wire 18. This same relay also connects the Wires 21 (connectedk to different impulse distributors) re impulse distributors)A and by the Wires 104 and 105. i

I'f the rstiinpulse distributor is disengaged the relay P is excited by the current passing through the following circuit:

l f-Pole of 4the central battery, Winding of relay P, rest contact of this relay, Wire 104, rest contact of relay O, Wire 102, Working contact of relay. K, Wire 21 of the lirst impulse distributor, rest contact of relay R (guarding f relay forthe impulse distributor) and -I-pole of the battery. f

`Whenthe relay P comes into action the contact ofthis Winding leaves the Wire 104 and "is again connectedy to the guard Wire 23 Which is connectedV tothe pole of the battery by means of the'Wire 17 and by means of the rest contact of the relay N (releasing relay. for the impulse distributors).

On the otherhand the relay P Which is in action connects (by means of the Wire 18, rest contact of relay N and Wire 20) the -pole of the battery to the Wire 22 connected to the Winding of the relay R connected to the -I- pole of the battery vthe relay Rthus comes into action. 1

The other Working contact of the relay P connects the pole of the battery to the Wire 106 Which results in the excitation of the relay O Which cuts the circuits 102.-.104 and '103- Moreoverthe Wire/16 being connected to the -l-.pole ofthebattery-.by reason of the locking of the relay E, therelay S oftheimpulse distributor comes immediately into action (by reason of the closure of the Lcircuit by means; of the Wire 28) and locksitself at the Sametime as the relay R. l Therelay Sincoming into action determines tlie coming into vvaction of the -relay T (dialing relay) by reason of the closing of rlPole of the centralbattery, Working relay R, Wire 26, vcontact, of the Workingrelay S, Wire 31,'contact of rest relay Uywire 32,

Winding` of the relayT, resistance r and V-pole of battery.

On the other hand in coming into action the relay K has produced the excitation of the relay L (by meansV of the Wire 17) and that of vthe relayl M'by means of the Wire :1-7, rest contactV of relay Nf,fWire` 34.

' The relay M'closes amongst others the contactsto Whichlleadthe Wires 17 and l15 Which Vresults in holding the relay K inv auto-excitation Whilst thegdialing impulses take place.Y

The operationsabove described take place almost instantaneously by the simple unhooking of the combination at the calling station. The circuit is therefore ready to receive the impulses ofthe dialing dial with a View to selecting the called station.

If the first impulse distributor was engaged its wire 21 will `have been separated from the +pole of the central battery by reason of the coming into action of the relay R; the -l-pole of the batteryv will have been connectedk to the wire 21 of the second distributor by means of the Wire 27 and the rest contact of the relay R. In this case the relay. I will have come into action andwill have engaged the second distributor.

If all the impulse.distributors are occupied the last ofthe relays connects the -l-pole of the'central battery (wire 27) yto the wire 33. If during occupation a combination is unhooked at another station the relay Q comes into action and connects (by means of the Wire'23) the wire 29, to the pole of the bat tery and excitesthe relay N which as hereinafter described releases the engaged signal.

In the following example it is assumed, that the station No. 17`calls the station No. 96.

For this purpose the first subscriber inserts his iirst finger into the Opening of the movabledialling discA opposite the Figure 9 and turns the disc in question. This movement of the dialling disc produces nine cutting operations of the line having for its object to interrupt nine times the excitation of the line relay E. This relay will connect and disconnect the pole of the-central battery nine times to and fromwires 15 and 16. Therelay S will occupy nine times VAthe position of rest and nine times in succession the rest position and nine times in succession the operating position. At the lirst interruption the relay S returns torest, cuts the circuit 26-31,Iand establishes the circuit 26'-110, contact ofworking relay, Wire 58, winding of relay U, resistance a and -pole of the battery. f

Simultaneously the relay S connects the wire 26 (-l-pole of the battery) to the winding of the relay V (intermittent guarding relay) by means of the wire 39'.V The relays U and V come into action.'`

In coming into action the relay U cuts the circuit Y 31-32 and establishes the circuit 31-59;V on the otherhand it closes the eX- citing circuit S7-458 cuts the circuit 40-61 andV closes the-circuit 40-41. The wire 26 (-I-pole of the battery) is then connected to the first` relay of thetens commutator by means of the following circuit.

+Pole of the battery, contactof working relay-R, kwire 26, contact of working relay wthe dialling relay f, wire;45, rest contact of the diallingrelay d, wire 46, rest Contact of the dialling relay b, wire 47, winding of the dialling relay a. 4

The relay a comes intoaction and holds itself in excitation, being connected to the -I-pole of the battery by means on the one hand, `of the wire 114, and on the other hand by the wires 48, 49, 50, 51, 52, 53, 54, 55, 56 and 57.

In coming into action the relay a connects, by means of its working contact, the wire 64 to thewire 65 and thus prepares the relay Z1 for the second impulse.

Y After the first interruption the relay S again comes into operation and cuts the circuits 26-39 and 26--110 and closes the circuit 26-3-1. The new circuit formed is as follows "W ire 26 (-l-pole of .the battery), working contact of relay S, wire 31, working contact of relay U, wire 59, common point of the winding of the relay T and the resistance r and the' pole of the battery. The relay T which has remained in auto-excitation by means of its working contact andthe wires 26 and 32 returns to rest, the two ends of this winding being placed at the same potential.

By the second interruption determined by the dialling disc, the relay S again comes to rest, cuts the circuit 26-31 and closes the circuits 26-110 and 26u39. The relay T being kept at rest the wire 110 is connected to the wire (common point of the winding of the relay U and of the resistance r1) and it is the relay which, this time, is short circuited as it is connected to the +pole of the battery, on the one hand, by the wires 37 and 58 and on the other hand by the wire 60.

The relay U, comes to rest and connects the wire 40 (-tpole of the battery) to the wire 61, the rest contact of the relay T, the wire 63, the rest Contact of the relay IV, the wire 64, the working contact of the relay a, the wire and the winding of the relay b.

The other end of this relay being branched to the pole of the battery, the relay b comes into operation and holds itself in auto-excitation by means of the wire 55.

When coming into operation the relay 5 `has broken the circuit 55-56; the relay a then again returns to rest.

1 The relay b has disengaged the wire 46 of the'relay a and established the circuit 46--66 and has thus prepared the relay c for the third impulse and so on.

It may be mentioned that the odd impulses are transmitted along the wire 42 and are recorded by one of the relays a, c, e, g, i, whilst the even impulses are transmitted along the wire 64 and are recorded by one that the relays T and U occupy the working Vposition for odd impulses, Whilst they occupy the rest position for even impulses.

After the ninth interruption, determined by the dialling` line, the relay z' of the commutator for the tens becomes locked and as the iigure 9 is the last of the series of the tens (asit is assumed that the called station is the station number 90) the relay i will be held in auto-excitation by means of its working contact and the wire 48.

Inthe working position the relay z' also establishes connection between the wires 73 and 74. The relay@ coming into action immediately the first impulse is transmitted by the dialling line remains excited by reason of its `special characteristics during the whole duration of the same series of impulses.

When it is locked the relay V connects, amongst others, the -l-pole of the battery to the wire 37 which leads to the winding of the relay X. (relay-for preparing the imitations) which immediately comes into action and holds itself excited until the relay V, which controls it, is unlocked.

It the time which lapses between two sevries Iof impulses is relatively long with re- -gardto two successive impulses, of the same series, the relay V has time to return to rest after the iirst series of, impulses and conv nects the Wire 26of the battery to the circuit formed by the wire 67,', the working contact of relay X (which is still in operation as it is sluggish), the wire 68, the rest contact of relay 1V, the wire 9, andthe winding of the relayW which comes into action in order to cut/out the circuits 41-42 and 63-64 and to establish the circuits 41--70 and 63-71 so that the second series ofimpulses is directed to a commutator for units which operatesV in r. t y

ing relay K, wire 17, contact of the working a similar manner-to that of the commutator for the tens.

rvShortly after the relayl comes to rest. At the end of the second Vseries of impulses the relay g/ comes into 'operation and remains locked by means ot its v'vorling'contact and 'the wire 114 which is always connected tothe .-l-rpole of the battery.'

' The relay z' of the commutator forthe tens and 1/ for the commutator for the units are thus excited. i f p p The numerical order of z' being 9 in the y commutator for the tens and that of g/ being 0 in the commutator for the units, there has been formed the number'QO. y

An instant after the end of the second series of impulses, .the relay V comes to to rest and connects the Wire 26` (-l-pole of battery) to the wire 67, the contact of the relay X, returned in the working position (at the same time as the relay V) the wire 68, the contact of the working relay W, the Wire72, the contact ofthe Working relay Y, (relay for placing the called lines under tenv time as X and the wirej73.

sion) which came into action at the. same The relay V'also connects the i-lpole of the Vbattery (by means of the v.working contact ot relay z') to thefwire 74 which leads to the winding of .the relaylZ9 (relay for the tens) representing the ninth tens. The same relay the rest contact' of relay B `of the called station, the wire' 79 and the restvcontact of relay D (relay for preparing the called side) V-tpoleof the battery to the winding of the said relay D which comes into action and is held in excitation by being branched tothe I -l-pole of the battery by the `rest relay B and the wire83. y

Shortly .after the Arela-yV has come to rest .the relay XA returns to rest, cuts the circuit (S7-68 and establishes the circuit (S7-113. By reason of this fact the -pole of the battery is connected tothewinding of the relay N by means of the rest relay V, the rest contact of relayuXv` wire 113, working contact of relay Y,'Wilre 30, contact fof working relay P and wire 29.

The relayN-` comes into-action; it releases on the one hand the impulse distributor which, from this moment becomes available for the establishment of a new communication; the relay N cuts, on the other hand',v the circuits 17-34 and establishes Vthe circuits 17-85 for connecting the wire 17,(+pole of the battery) tothe relay C Vot the called subscriber, this connection being obtained by the closing of the following circuit.

+Pole ofthe battery, contact of the working ofrelay J, Wire 86, second working contact ofy relay M, wire 85, multiplied at all the relays D, wire 84, working contact of re-k lay D corresponding to the called station, wire 8 and relay()2 of the called station.

This relay of whichone end of the winding' is connected to the pole of the battery comes into action, cuts its windingfromthe wire 8 `and connects it with the wire 14 the relay B of the called subscriber comes into action and cuts on the one hand the guarding circuit of the relay D which vreturns to rest and on the other hand cuts ot the supply to the line.

In coming` into action the relay C2 reconnects, on the one hand, the wires 4'and 5 to the wires 11 and 12, on the other hand, the wires 88 and 89 to the Wires 90 and 91.`

As the relay A remains at rest kWhen the station is the called station the wires 4 and 5 are separated. The line of the called station is thus branched by means of the rest relay A to the Wires 88 and 89. Whenthe relay isin roperation the wires 88 .and ,89 are yconl nected to the calling .relay H. Shortly after `the coming'into action of the relays J and C2, the sluggish relay M, from which the supply has been cut oli' by the relay N,-returns to rest, cuts the circuit -87 and closes the `circuit 35--36 for the purpose of reconnecting the -l-pole of the :battery to the wire 96 Whichdetcrmines the bringinginto operation of the calling apparatus.

The calling lcurrent supplied by the wire 98 passesthroughthe line of the called station by reason of the formation of the following circuit:

VlVire 98, rest contact of relay H, wire 90, contact of relay C2 of the called subscriber, which is in operation, wire 88, contact of the rest relay A, wire l, condenser and bell or" the called subscriber, wire 2, second rest contact of relay A, wire 89, second Contact of working relay C2, wire 91, second contact .of rest relayI-I (calling relay for the line), winding of relay H and pole of the battery. i The relay H is not'excited when its wind- 'ing is traversed by alternating current Ybut is excited when its winding is traversed by continuous` current.

`When the called subscriber has unhooled his combination and consequently disconnected his condenser" fromthe line a continuous current passes through the line. rlhe relay H comes into action and holds itself in auto-excitation by thewire 36.

The relay H thus interrupts the calling circuitand establishes the circuits -93 and 91-92.

The `rela-y G (speakingrelay on the'called side) which constitutes the self supply of the called subscriber comes into action and defin nitely loops the speaking circuit by closing the circuits 93-95 and 92-94. From this moment conversation can take place.v

For releasing the circuit at the end of the communication `it is necessary for theV two ,I subscribers to suitably rehook` their combiv nation-s. Y

. In `order to preyent a subscriber from forgetting to rehoolchis combination the first ofthe two subscribers who normally elfects Vthis operation determines the transmission,

to his correspondent, of a conventional phonic signal hang up. This signal which is received inthe receiver of the station of `which the combination `has not yet been hooked up is continuous and sufficiently strongl so as to enableitito be heard at some meters -from the instrument. *i

If it is assumed that it is the called statio-nwhere the combination is hung up lirst the wire'V 17 is connected to the wire 107v by the relay H which is in operation. In coming to rest therelay G connect-s. by its rest contact, the wire 17 `('lpole of the battery) to the wire IOSWhichfleads to the winding r vofthe relay SR.

This relay Lcomes into action and determines by means ot the wire 109 the transmission ofthe signal hang up over the calling line. If however it is the calling station where the ccmbination has been hung up` iirstthe relay E ellfects a similar operation to that above described and the signal hang up is transmitted to the called station.

When the combinations have been hung up on both stations the relays E and G come to rest and cut the speaking line from the central battery. The relay K comes to rest immediately and the short interval of time which elapses between the unlocking of the relay K and the unlocking of the sluggish relay J (differentiation relay between the called, free or engaged line) enables the relays B and C of the called station and of the calling station to return to rest. Vhen the relay L subsequently comes to rest it connects the pole of the battery to the wire 13 for preparing the circuit for the establishment of a fresh communication.

If in the case under consideration the subscribers station No. 90 had been engaged the relay J would not have been able to return to the loclincf position and the sluggish relay M, in comino to rest, would have'connectedthe wires l?? (-l-pole `of the battery) tothe Winding of the relay F (engaged relay) by means of the wire 35, the rest Contact of the relay M, the wire 36, the rest contact of the relay J and the wire 97. Y,

The relay F thus excited closes the operating circuit (M -m) of the signalling device and connects the wire of the line 95 to the engaged lcircuit by means of the wire 38.

The conventional signal is thus noticed in the receiver of the calling subscriber who will thus hang up his combination so as to release the central members.

The improved automatic select-ing circuit adapted for telephony or the ytransmission ot signals to a distance and Aillustrated diagrammatically in `one form of construction maybe provided withany suitable number of subscribers stations andthe members illustrated in the drawing may be of a size, dimensions, proportions and constitution of anyr suitable natu-re 4without departing the scope ot the present invention which is Vcharacterized by the fact that in relation to automatic telephone systems proposed and carried out hitherto, the new device le scribed above onlyvrequires with an equal number oi subscribers very simple standardized members of reduced number whilst ensurino' considerable security in the estal terminating a conversation line `(lll), i3

ers line with the outgoing trunk (4, 5), the l said two links (88, 89 and 4, being` individual to each equipment (I) of a subscribers station.

2. An automatic relay selector circuit for telephony as set forth in claim 1, in which the incoming and outgoing links (88, 89 and 4, 5) of each individual equipment (I) of the subscribers station intersects a network of trunk lines (II), the number of which is only a fraction ofthe number of the subscribers lines, said trunk lines each comprising, arranged in parallel, an incoming trunk (90, 91), an outgoing trunk (11, 12), a circuit (85) for controlling the incoming trunk, a. circuit (9) for controlling theoutgoing trunk and a locking circuit (13), means for causing each intersecting of the trunks of a subscribers station with atrunk line, including a single selector relay (C1, C2, C3 effecting simultaneously, when it is operative,'and by means of two pairs of contacts, on the one hand, the connection of the incoming link with the incoming trunk (90, 91) and, on the other hand, the connection of the outgoing link (4, 5) with the outgoing trunk (11, 12) one of the two links being automatically insulated from the corresponding subscribers line (1, 2) by the reversing relay (A) from the said subscribers line, selectively according to Whether the said subscriber is the calling or the called party.

3. Automatic relay selector circuit for telephony as set forth in claim 1 each individual equipment (I) of the subscribers line com prising two connecting relays (D, D1), each having as many contacts as there are trunk o lines (II), the movable'contacts of these two relays being, on the one hand, connected in multiple between each other, and, on the other hand, connected respectively to the selector relays (Cl, C2, C3 serving said individual equipment of the subscribers line, the work contacts of one connecting relay (D1) being connected respectively with the control circuit (9) of the Aoutgoing trunk (11, 12) of the corresponding trunk lines and operating when the station is the calling party, while the work contacts of the other connecting relay (D) are connected respectively to the control circuit of the incoming trunk (88, 89) of the same trunk lines and operate when this station is called, this latter relay comprising in addition a prime .circuit (78, 7 9) and a circuit (83) for sustaining its auto-excitation Y 4. An automaticrelay telephone selector circuit as set forth in claim 1, including conv densers and a conversation line connectincr together the outgoing trunk (11, 12) and the incoming trunk r(90, 91) ofthe same trunk line (II), the several lines being'mounted in cascade and each line comprising a feed group which is formed by. two relays (IE-G), feeding respectively the outgoingr and thel incomingtrunks, the feed relays of the outgoing trunk, rby means of its work contacts, controlling a keeper,` (K), in its turn controlling a guard relay (L) vfor liber-k ating the who-le automatic selecting circuit, and, on the other hand, a reducer relay to close the excitation circuit of the selector relay (C1, C2, C3. of the called subscriber, .said selector relay beingadapted to be put in series with a pilot relay (J) closing equally the circuit (96) of the call signal and the circuit (97 of the busy signal.

5. An automatic relay telephone selector circuit, said circuit comprisingin combina` tion with individual equipment (I) of the subscribers lines and anetworkof .trunk lines (II), a connecting circuit (V) common tov a plurality of markers (IV), fin ytheir turn forming a circuit common to all: thetrunk lines (II), each of the counting groups (IV) comprising r'a plurality of counting chains, each formed of ten counting relays, the number of said chains corresponding to the number of digits forming the subscribers number, each of the counting chains being actu-V ated respectively according to the number ing of the units, the tens and so on, and the relays composing each chain serving respectively the decimal groups in connection with which the chain is actuated.

6. In anfautomatic relay telephone selector circuit, as set forth inclaim 5, the counting be the rank they occupy in the decimalorder, said chains each including relays excited by means of two distinct circuits (42 to 47 and 48 to 57), one of which is traversed by the odd impulses of the current traversing the rest contact of each of the even relays, the other circuit being traversed by the even impulses shunted on each of the odd relays.

7 An automatic relay telephone selector circuit, as set forth in claim 5, including an impulse distributor relay preceding all the counting chains of the same marker group (IV) said relay subdividingthecurrent impulses emitted by the counting dial of a subscribers station into odd impulses which are directed on to the Aodd counting relays of a counting chain relay andinto even impulses which are directed on to the even counting relays of said counting chain.

8. An automatic relay selector circuit comprising counting groups, the relay impulse lSO an Lid distributor of each marker group (IV) being c combined with a commutation device o'l'l tlie decimal order form, tvvo control relays (V, X) and a reversing relay (W), the two control relays acting reciprocally soas to direct the current impulses emitted by the numbering or counting dial respectively on to the different counting chains, beginning With those corresponding to tlie highest rank in the decimal order.

9. An automatic relay telephone selector circuit comprising, in combination With individual equipments (I) of the subscribers line and with a network of trunk lines (II), each terminated by a conversation line (III) of counting groups (IV), eachV preceded. by an impulse regulator, said automatic circuitbeing characterized by the fact that allthe counting groups are connected to a single connecting group chain circuit (V), formed by ten relays (Z), controlled individuallyby a Work contact oi each of the counting relays of the counting chains of the decimals (tens) of each counting gro-up, each of said relays (Z) of the connecting circuit controlling in turn ten contacts, the fixed Ypart of which ends at'the control circuit of a called subscribers` line, the movable part ofA each of said contacts ter1ninat ing at the work contact of each of tlie counting relays of the counting chain of the units in each of the marker groups (IV).

MICHEL TCHOUBRITCI-I. 

